Anti-microbial antiperspirant products

ABSTRACT

Anti-microbial products comprising an antiperspirant active and an amount of transition metal chelator sufficient to enhance the deodorancy performance of said antiperspirant active, are claimed. The transition metal chelator salt improves the anti-microbial performance of the antiperspirant active and the two components can be co-formulated. Particular products are antiperspirant deodorant compositions. Preferred chelator salts have high affinity for iron (III).

FIELD OF INVENTION

This invention relates to the field of anti-microbial compositions andto methods of reducing microbial numbers. In particular, this inventionis concerned with reducing microbial numbers upon the surface of thehuman body and thereby reducing body odour. The compositions and methodsinvolved utilise a transition metal chelator together with anantiperspirant active. When used on the human body, the compositions andmethods of the invention are of greatest benefit when used on the mostmalodorous areas of the body, for example the underarm areas or feet.

BACKGROUND

Typically, a deodorising composition will attempt to significantlyreduce or prevent body odour by reducing either perspiration or thenumber of viable micro-organisms on the body surface as representedherein by skin. The former is usually referred to as an antiperspirantcomposition and the latter a deodorant. Other compositions attempt tomask body malodours using perfumes.

Compositions reducing perspiration often comprise a metal salt, such asan aluminium or zirconium salt, which blocks the sweat pores. Thismethod is very simple and has proven to be beneficial, yet perspirationis rarely reduced by more than 50%.

Deodorants, on the other hand, reduce the numbers of viablemicro-organisms on the surface of the skin. It is well known that sweatis usually odourless until it has been degraded by the skin microflora.Typical deodorants include ethanol and triclosan (2′,4,4′-trichloro,2-hydroxy-diphenyl ether) which is a well known anti-microbial agent.However, the deodorising effect obtained with such deodorants wears offwith the passage of time and the microflora progressively recover theirnumbers.

There is, therefore, a continuing requirement for effective and longlasting antiperspirant deodorant compositions for the market. Theproblem to be solved is not simply reducing sweating and initialmicrobial numbers on the body surface; equally important is maintaininglow microbial numbers (particularly low bacterial numbers) on the bodysurface (particularly in the most malodorous areas, eg. the axilla).

Transition metal chelators have previously been incorporated intoantiperspirant deodorant compositions as formulation aids. U.S. Pat. No.5,516,511 (Procter and Gamble Co.) discloses particular antiperspirantgel compositions in which chelators are used during manufacture toprevent reaction between the active and the primary gellant, the lattercomponent comprising 12-hydroxystearic acid or a derivative thereof.U.S. Pat. No. 5,849,276 (Procter and Gamble Co.) mentions chelators inantiperspirant stick compositions, although such materials are stated tobe optional “non-active” components. The gellants exemplified in thispatent are again 12-hydroxystearic acid and derivatives thereof, andalso N-lauroyl-glutamic acid dibutyl amide and2-dodecyl-N.N′-dibutyl-succinamide.

Transition metal chelators have also been disclosed in simple deodorantcompositions, that is to say, deodorant compositions excludingantiperspirant actives. U.S. Pat. No. 4,356,190 (Personal Products Co.)discloses the use of selected aminopolycarboxylic acid compounds forinhibiting malodour formation; WO 97/01360 (Concat Ltd.) claims a methodof inhibiting bacterial growth using particular substituted polyazacompounds that show affinity for first transition series elements; WO97/44006 (Ciba Speciality Chemicals Holding, Inc.) claims the use ofnitrogen-containing complexing agents for the anti-microbial treatmentof the skin and of textile fibre materials; and WO 97/02010 disclosesthe use of chelators selected from the succinic acid, glutaric acid, andphosphonic acid classes as bactericidal compounds.

Other patents indicate that transition metal chelators can improve theefficacy of specific known anti-microbials. WO 98/12399 (Public HealthResearch Institute of the City of New York) discloses improvedperformance of lanthionine-containing bacteriocins in compositions alsocomprising a transition metal chelator. WO 97/09974 (Laboratoire Medix)discloses compositions comprising chlorhexidine and a chelator. EP0019670 B1 (Glyco Chemicals, Inc.) discloses anti-microbial compositionscomprising a condensation product of 5,5-dimethyl hydantoin andformaldehyde in combination with a water-soluble chelating agentselected from ethylenediaminetetraacetic acid (EDTA),diethylenetriaminepentaacetic acid (DTPA) or the alkali metal saltsthereof. U.S. Pat. No. 4,199,602 (Economics Laboratory, Inc.) disclosesthe potentiation of anti-microbial nitroalkanes by aminocarboxylic-typechelating agents. U.S. Pat. No. 5,688,516 (University of Texas System etal) discloses compositions comprising non-glycopeptide anti-microbials(other than vancomycin) in combination with a selection of components,including a chelating agent. WO 99/10017 (University of Texas System etal) discloses a method for controlling the growth of micro-organismsusing a chelating agent and an anti-microbial agent. GB 1,420,946(Beecham Group Ltd.) discloses that the activity of selected phenolicanti-microbials can be vastly increased by certain chelating agents, inparticular the disodium salt of EDTA.

SUMMARY OF THE INVENTION

It has been discovered that the combined use of an antiperspirant activeand an effective amount of a transition metal chelator givessurprisingly good and long-lasting anti-microbial benefits. When suchtreatment is applied to the human body, highly effective malodourcontrol results. An important function of the antiperspirant active isto reduce initial microbial numbers on the surface being treated, whilstthe transition metal chelator functions to augment the maintenance oflow microbial numbers. Surprisingly, it has been found that the twocomponents can be used together without detrimental interactionsaffecting either the performance of the components or the stability ofcompositions containing both the components. On application to the humanbody, additional hygiene and malodour control derive from theantiperspirancy benefit also delivered.

According to a first aspect of the present invention, there is providedan anti-microbial product comprising an antiperspirant active and anamount of transition metal chelator sufficient to enhance the deodorancyperformance of said antiperspirant active.

According to a second aspect of the present invention, there is provideda method of controlling microbial numbers comprising the application toa substrate of a product comprising an antiperspirant active and anamount of transition metal chelator sufficient to enhance the deodorancyperformance of said antiperspirant active. A particular application ofthis aspect of the invention is the control of microbial numbers on thesurface of the human body, for example skin, and the resulting controlof body odour. This particular application also provides a method forreducing perspiration and providing additional control of bacterialnumbers on the body surface, eg. skin surface. This method may also beused to deliver enhanced fragrance intensity from a fragrance-containingproduct according to the invention.

According to a third aspect of the present invention, there is provideda method for the manufacture of an anti-microbial composition comprisingthe mixing of an antiperspirant active, a transition metal chelator, anda carrier fluid.

DETAILED DESCRIPTION

The antiperspirant active and the transition metal chelator bothfunction as effective anti-microbial agents in this invention. Onapplication to the human body, the reduced perspiration benefitdelivered by the antiperspirant active is also beneficial and furthercontributes to the deodorancy benefit resulting from the anti-microbialperformance of the components of the product. Without wishing to bebound by theory, it is hypothesised that after reduction of microbialnumbers by the antiperspirant active, the transition metal chelatoreffectively inhibits the up-take of essential transition metal ionnutrients by the remaining microbes, thereby minimising their re-growth.Surprisingly, there is no detrimental interaction between theantiperspirant active and the transition metal chelator and an excellentanti-microbial and deodorancy performance is obtained from the productsof the invention.

It is not essential that the antiperspirant active and the chelator arepart of the same composition. The anti-microbial benefit derived fromuse of the invention may be gained by independent application of theantiperspirant active and the chelator. Such application may beconcurrent or consecutive, provided that the treated substrateexperiences the presence of both components at the same time. When thecomponents are applied from independent compositions, it is preferredthat the product also comprises a means for, and/or instruction for,both of the compositions to be applied to the substrate requiringtreatment.

It is preferred that the anti-microbial product of the inventioncomprises an antiperspirant active and a transition metal chelator thatare both present in the same composition. The benefits found with suchcompositions can include good product aesthetics, lack of productseparation, attainment of the desired rheology, visco-stability, gooddispensing, and any combination of these benefits or others.

The method of controlling microbial numbers offered by the invention isparticularly useful because the benefit can extend for many hours, forexample 5 hours, or 24 hours, or even longer, after application of theproduct to the substrate. When the substrate is the skin of the humanbody, this can result in an extended deodorancy benefit; that is to say,extended inhibition of generation of human body odour.

The antiperspirant active and the chelator may be present in thecomposition or compositions of the invention in any form. For example,either or both of the agents may be used neat or may be diluted with avolatile propellant and used as an aerosol; with an additional liquidand used, for example, as a roll-on or squeeze-spray product; or with athickener or structurant and used, for example, as a cream, gel or solidstick product.

The anti-microbial product of the invention may be applied to thesubstrate requiring treatment by any means. Frequently, the substraterequiring treatment is a surface. Application of liquid compositions canbe by absorption onto a carrier matrix like paper, fabric, or sponge andapplication by contacting said carrier matrix with the surface. Solid orsemi-solid compositions can be applied by direct contact or can bedissolved or dispersed in a liquid medium prior to application.Application can also comprise a combination of any two or more of theabove techniques.

Chelators

Preferred transition metal chelators have affinity for iron (III),preferably high affinity for iron (III); that is to say, a bindingconstant for iron (III) of greater than 10¹⁰, or, for optimumperformance, greater than 10²⁶. The ‘iron (III) binding constant’referred to above is the absolute stability constant for thechelator-iron (III) complex. Such values are independent of pH and aremeasured on the most anionic, fully deprotonated form of the chelator.Measurements can be made potentiometrically, and in a number of otherways. Full details of suitable methods can be found in “Determinationand Use of Stability Constants”, A. E. Martell and R. J. Motekaitis(VCH, New York, 1989). Tables of applicable values may be found innumerous sources, for example “Critical Stability Constants”, R. M.Smith and A. E. Martell (Plenum Pub. Corp., 1977).

Preferred chelators are “micro-molar active”; that is to say, they areable to significantly inhibit the growth of a relevant micro-organismwhen present, in a medium containing said micro-organism, at aconcentration of 3×10⁻⁶ mol.dm⁻³ or less. Inhibition is consideredsignificant when growth of the relevant micro-organism on a supportingmedium can be reduced by at least 30%, preferably by at least 45%. Whenthe surface to be treated is human skin, a relevant micro-organism isStaphlococcus epidermidis and chelators capable of achieving significantinhibition include diethylenetriaminepentaacetic acid (DTPA) andtriethylenetetraaminehexaacetic acid (TTHA), but excludeethylenediaminetetraacetic acid (EDTA) andtrans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CDTA).

The chelator may be used in its acid form, but it may also be used asone of its salts.

The iron (III) chelators used in the present invention preferably haveacid forms with at least two, more preferably at least four, and mostpreferably at least five, ionisable acid groups. The acid groups arepreferably carboxylic and/or phosphonic, but may be sulphonic orphosphinic, or any mixture of these groups.

Preferred chelators with phosphonic acid groups are, in the acid form,diethylenetriaminepenta(methylphosphonic) acid (DTPMP),ethanehydroxydiphosphonic acid (EHDP),ethylenediaminetetra(methylenephosphonic acid) (EDTMP), andhexamethylenediaminetetra(methylenephosphonic acid) (HMDTMP).

Particularly suitable chelators for use include polycarboxylatecompounds, in particular aminopolycarboxylate compounds. The acid formsof the aminopolycarboxylate compounds include EDTA, CDTA,ethylenediaminedisuccinic acid (EDDS). More preferredaminopolycarboxylate chelators have the acid forms DTPA, TTHA, andethylenebis[2-(2-hydroxyphenyl)glycine] (EDDHA).

The chelators or salts thereof preferably have only moderate molecularweight, by which it is meant that the chelators, in their acid forms,have a molecular weight of less than 1000, more preferably 200 to 800,and most preferably 290 to 580, and in their salt form have a molecularweight of less than 2000, more preferably 300 to 1400, and mostpreferably 500, to 1000.

The chelator is preferably incorporated into a composition at a level of0.01% to 10%, more preferably at a level of 0.05% to 5%, and mostpreferably at a level 0.3% to 3% by weight of the non-volatilecomponents of the composition. Mixtures of chelator salts may also beused. In aerosol compositions comprising greater than 50% by weight ofvolatile propellant a preferred level of chelator may be 0.5% to 8% byweight of the non-volatile components of the composition.

Herein, non-volatile components are those having a boiling point greaterthan 20° C. at atmospheric pressure.

As already mentioned, the chelator may be used in its acid form or asone of its salts. Preferred salts, for certain applications, aremonovalent alkali metal salts such as sodium and potassium salts. Forcertain other applications, for example formulation in alcohol-basedcompositions, salts with organic counter-ions are preferred, for exampleprotonated or quaternised amines. Salts formed using aliphatic aminesare generally preferred to those formed from aromatic amines. A furtherpreference is for protonated or quaternised amine cations possessing aC₁-C₁₀ terminal hydrocarbyl group, wherein a hydrocarbyl group is aradical comprising solely carbon and hydrogen atoms. Such relativelyhydrophobic organic counter-ions lead to particularly good compatibilitybetween the chelator salt and the organic anti-microbial.

Preferred protonated or quaternised amine cations of the chelator saltsare of formula R¹R²R³R⁴N⁽⁺⁾, wherein R¹ is H or CH₃; R², R³, and R⁴ areeach independently H or an aliphatic or aromatic substituent containing0 to 3 hydroxyl groups, optionally interrupted and/or substituted byfunctional groups such as ether, amine, ester, or amide; with theprovisos that at least one of R², R³, or R⁴ comprises a C₁-C₁₀ terminalhydrocarbyl group, optionally R² and R³ together forming a ring as theterminal hydrocarbyl group, and that R², R³, and R⁴ are not allCH₂CH(OH)CH₃ groups.

Particularly preferred chelator-amine salts are salts of2-amino-2-methyl-1-propanol, cyclohexylamine, diisopropanolamine, or2-amino-1-butanol.

Partial salts of chelator acids possessing more than one acidic groupmay also be employed; such salts retain one or more non-ionised acidgroups. Also claimed are salts where the cations are in part protonatedor quaternised amines and in part some other cation, for example analkali metal cation, in particular a sodium ion.

Antiperspirant Actives

Antiperspirant actives are preferably incorporated into a composition inan amount of from 0.5-60%, particularly from 5 to 30% or 40% andespecially from 5 or 10% to 30 or 35% of the weight of the composition.The ratio of chelator and/or salt thereof to antiperspirant active ispreferably from 1:3 to 1:50 and more preferably from 1:5 to 1:25 byweight.

Antiperspirant actives for use herein are often selected from astringentactive salts, including in particular aluminium, zirconium and mixedaluminium/zirconium salts, including both inorganic salts, salts withorganic anions and complexes. Preferred astringent salts includealuminium, zirconium and aluminium/zirconium halides and halohydratesalts, such as chlorohydrates.

Aluminium halohydrates are usually defined by the general formulaAl₂(OH)_(x)Q_(y).wH₂0 in which Q represents chlorine, bromine or iodine,x is variable from 2 to 5 and x+y=6 while wH₂O represents a variableamount of hydration. Especially effective aluminium halohydrate salts,known as activated aluminium chlorohydrates, are described in EP 006,739(Unilever PLC and NV). Some activated salts do not retain their enhancedactivity in the presence of water but are useful in substantiallyanhydrous formulations, i.e. formulations that do not contain a distinctaqueous phase. Aluminium halohydrates as described herein areparticularly preferred in aerosol compositions.

Zirconium actives can usually be represented by the empirical generalformula: ZrO(OH)_(2n-nz)B_(z).wH₂O in which z is a variable in the rangeof from 0.9 to 2.0 so that the value 2n-nz is zero or positive, n is thevalency of B, and B is selected from the group consisting of chloride,other halide, sulphamate, sulphate and mixtures thereof. Possiblehydration to a variable extent is represented by wH20. Preferable isthat B represents chloride and the variable z lies in the range from 1.5to 1.87. In practice, such zirconium salts are usually not employed bythemselves, but as a component of a combined aluminium andzirconium-based antiperspirant.

The above aluminium and zirconium salts may have coordinated and/orbound water in various quantities and/or may be present as polymericspecies, mixtures or complexes. In particular, zirconium hydroxy saltsoften represent a range of salts having various amounts of the hydroxygroup. Zirconium aluminium chlorohydrate may be particularly preferred.

Antiperspirant complexes based on the above-mentioned astringentaluminium and/or zirconium salts can be employed. The complex oftenemploys a compound with a carboxylate group, and advantageously this isan amino acid. Examples of suitable amino acids include dl-tryptophan,dl-β-phenylalanine, dl-valine, dl-methionine and β-alanine, andpreferably glycine which has the formula CH₃CH(NH₂)COOH.

It is highly desirable to employ complexes of a combination of aluminiumhalohydrates and zirconium chlorohydrates together with amino acids suchas glycine, which are disclosed in U.S. Pat. No. 3,792,068 (Procter andGamble Co.). Certain of those Al/Zr complexes are commonly called ZAG inthe literature. ZAG actives generally contain aluminium, zirconium andchloride with an Al/Zr ratio in a range from 2 to 10, especially 2 to 6,an Al/Cl ratio from 2.1 to 0.9 and a variable amount of glycine. Activesof this preferred type are available from Westwood, from Summit and fromReheis.

Other actives that may be utilised include astringent titanium salts,for example those described in GB 2,299,506.

The proportion of solid antiperspirant salt in a composition normallyincludes the weight of any water of hydration and any complexing agentthat may also be present in the solid active. However, when the activesalt is in solution, its weight excludes any water present.

If the composition is in the form of an emulsion the antiperspirantactive will be dissolved in the disperse phase. In this case, theantiperspirant active will often provide from 3 to 60% by weight of theaqueous disperse phase, particularly from 10% or 20% up to 55% or 60% ofthat phase.

Alternatively, the composition may take the form of a suspension inwhich antiperspirant active in particulate form is suspended in thewater-immiscible liquid carrier. Such a composition will probably nothave any separate aqueous phase present and may conveniently be referredto as “substantially anhydrous” although it should be understood thatsome water may be present bound to the antiperspirant active or as asmall amount of solute within the water-immiscible liquid phase. In suchcompositions, the particle size of the antiperspirant salts often fallswithin the range of 0.1 to 200 μm with a mean particle size often from 3to 20 μm. Both larger and smaller mean particle sizes can also becontemplated such as from 20 to 50 μm or 0.1 to 3 μm.

Additional Components

An additional component that can sometimes augment the efficacy of thecomposition is a further organic anti-microbial agent. Most of theclasses of agents commonly used in the art can be incorporated intocompositions of the invention. Levels of incorporation are preferablyfrom 0.01% to 3%, more preferably from 0.03% to 0.5%. Preferred organicanti-microbial agents have a minimum inhibitory concentration (MIC) of 1mg.ml⁻¹ or less, particluarly 200 μg.ml⁻¹ or less, and especially 100μg.ml⁻¹ or less. The MIC of an anti-microbial agent is the minimumconcentration of the agent required to significantly inhibit microbialgrowth. Inhibition is considered “significant” if an 80% or greaterreduction in the growth of an inoculum of a relevant micro-organism isobserved, relative to a control medium without an anti-microbial agent,over a period of 16 to 24 hours at 37° C. The “relevant micro-organism”used for testing should be representative of those associated with thesubstrate to be treated. When the substrate to be treated is human skin,a relevant micro-organism is Staphylococcus epidermidis. Other relevantmicro-organisms include Coryneform spp., Salmonella spp., EscherichiaColi, and Pseudomonas spp., in particular P. aeruginosa. Details ofsuitable methods for determining MICs can be found in “AntimicrobialAgents and Susceptibility Testing”, C. Thornsberry, (in “Manual ofClinical Microbiology”, 5^(th) Edition, Ed. A. Balows et al, AmericanSociety for Microbiology, Washington D.C., 1991). A particularlysuitable method is the Macrobroth Dilution Method as described inChapter 110 of above publication (pp. 1101-1111) by D. F. Sahm and J. A.Washington II. MICs of anti-microbials suitable for inclusion in thecompositions of the invention are triclosan: 0.01-10 μg.ml⁻¹ (J. Regoset al., Dermatologica (1979), 158:. 72-79) and farnesol: ca. 25 μg.ml⁻¹(K. Sawano, T. Sato, and R. Hattori, Proceedings of the 17^(th) IFSCCInternational Conference, Yokahama (1992) p. 210-232). By contrastethanol and similar alkanols have MICs of greater than 1 mg.ml⁻¹.Preferred organic anti-microbials are bactericides, for examplequaternary ammonium compounds, like cetyltrimethylammonium salts;chlorhexidine and salts thereof; and diglycerol monocaprate, diglycerolmonolaurate, glycerol monolaurate, and similar materials, as describedin “Deodorant Ingredients”, S. A. Makin and M. R. Lowry, in“Antiperspirants and Deodorants”, Ed. K. Laden (1999, Marcel Dekker, NewYork). More preferred anti-microbials for use in the compositions of theinvention are polyhexamethylene biguanide salts (also known aspolyaminopropyl biguanide salts), an example being Cosmocil CQ™available from Zeneca PLC, preferably used at up to 1% and morepreferably at 0.03% to 0.3% by weight; 2′,4,4′-trichloro,2-hydroxy-diphenyl ether (triclosan), preferably used at up to 1% byweight of the composition and more preferably at 0.05-0.3%; and3,7,11-trimethyldodeca-2,6,10-trienol (farnesol), preferably used at upto 1% by weight of the composition and more preferably at up to 0.5%.

A carrier fluid is a highly desirable additional component of many ofthe compositions of the invention. Such materials act as solvents orcarriers for the other components of the composition, facilitating theirdelivery. Water can be used as a carrier fluid, although it is morepreferable to use mixtures of water and an alcohol, especially ethanol.Alcohol/water mixtures are particularly suitable carrier fluids inroll-on and pump spray products. Cyclomethicones and other volatilesilicones are another class of carrier fluid that may be employed.Examples of this latter class are Dow Corning silicone fluids 344, 345,244, 245, 246, 556, and the 200 series; Union Carbide Corp. silicones2707 and 7158; and General Electric silicone SF1202. Alternatively,non-silicone hydrophobic liquids may be employed, such as mineral oils,hydrogenated polyisobutene, polydecene, paraffins, isoparaffins of atleast 10 carbon atoms, and aliphatic and aromatic ester iols. Propyleneglycol, butylene glycol, and related glycols may also be used. Otheralternative carrier fluids include materials having multiple functions,for example isopropyl myristate, isopropyl palmitate, dipropyleneglycol, and glycerol. Mixtures of carrier fluids may also be employed toadvantage. Compositions preferably comprise carrier fluid at a level offrom 30% to 98% by weight, or more preferably from 60% to 97% by weight,of the non-volatile components of the composition.

Structurants and emulsifiers are further additional components of thecompositions of the invention that are highly desirable in certainproduct forms. Structurants, when employed, are preferably present atfrom 1% to 30% by weight of the composition, whilst emulsifiers arepreferably present at from 0.1% to 10% by weight of the composition. Inroll-ons, such materials help control the rate at which product isdispensed by the roll ball. In stick compositions, such materials canform gels or solids from solutions or suspensions of the chelator saltin a carrier fluid. Suitable structurants for use in such compositionsof the invention include cellulosic thickeners such as hydroxy propylcellulose and hydroxy ethyl cellulose, and dibenzylidene sorbitol.Emulsion pump sprays, roll-ons, creams, and gel compositions accordingto the invention can be formed using a range of oils, waxes, andemulsifiers. Suitable emulsifiers include steareth-2, steareth-20,steareth-21, ceteareth-20, glyceryl stearate, cetyl alcohol, cetearylalcohol, PEG-20 stearate, and dimethicone copolyol. Suspension aerosols,roll-ons, sticks, and creams require structurants to slow sedimentation(in fluid compositions) and to give the desired product consistency tonon-fluid compositions. Suitable structurants include sodium stearate,stearyl alcohol, cetyl alcohol, hydrogenated castor oil, syntheticwaxes, paraffin waxes, hydroxystearic acid, dibutyl lauroyl glutamide,alkyl silicone waxes, quaternium-18 bentonite, quaternium-18 hectorite,silica, and propylene carbonate. Some of the above materials alsofunction as suspending agents in certain compositions.

Further emulsifiers desirable in certain compositions of the inventionare perfume solubilisers and wash-off agents. Examples of the formerinclude PEG-hydrogenated castor oil, available from BASF in theCremaphor RH and CO ranges, preferably present at up to 1.5% by weight,more preferably 0.3 to 0.7% by weight. Examples of the latter includepoly(oxyethylene) ethers.

Certain sensory modifiers are further desirable components in thecompositions of the invention. Such materials are preferably used at alevel of up to 20% by weight of the composition. Emollients, humectants,volatile oils, non-volatile oils, and particulate solids which impartlubricity are all suitable classes of sensory modifiers. Examples ofsuch materials include cyclomethicone, dimethicone, dimethiconol,isopropyl myristate, isopropyl palmitate, talc, finely-divided silica(eg. Aerosil 200), particulate polyethylene (eg. Acumist B18),polysaccharides, corn starch, C12-C15 alcohol benzoate, PPG-3 myristylether, octyl dodecanol, C7-C14 isoparaffins, di-isopropyl adipate,isosorbide laurate, PPG-14 butyl ether, glycerol, hydrogenatedpolyisobutene, polydecene, titanium dioxide, phenyl trimethicone,dioctyl adipate, and hexamethyl disiloxane.

Fragrance is also a desirable additional component in the compositionsof the invention. Suitable materials include conventional perfumes, suchas perfume oils and also include so-called deo-perfumes, as described inEP 545,556 and other publications. Levels of incorporation arepreferably up to 4% by weight, particularly from 0.1% to 2% by weight,and especially from 0.7% to 1.7% by weight.

It should be noted that certain components of compositions perform morethan one function. Such components are particularly preferred additionalingredients, their use often saving both money and formulation space.Examples of such components include ethanol, isopropyl myristate, andthe many components that can act as both structurants and sensorymodifiers, for example silica.

Further additional components that may also be included are colourantsand preservatives at a conventional concentration, for example C₁-C₃alkyl parabens.

Product Forms

The compositions of the invention may take any form. Examples includewax-based sticks, soap-based sticks, compressed powder sticks,. roll-onsuspensions or solutions, emulsions, gels, creams, squeeze sprays, pumpsprays, and aerosols. Each product form contains its own selection ofadditional components, some essential and some optional. The types ofcomponents typical for each of the above product forms may beincorporated in the corresponding compositions of the invention.

Particular embodiments of the invention are anti-microbial productscomprising an antiperspirant active and an amount of transition metalchelator sufficient to enhance the deodorancy performance of saidantiperspirant active, that are not gel-solid stick compositions gelledby 12-hydroxystearic acid, esters of 12-hydroxystearic acid, amides of12-hydroxystearic acid, N-lauroyl-glutamic acid dibutyl amide, and2-dodecyl-N,N′-dibutyl-succinamide.

Embodiments of the invention of this type include liquid and soft solidcompositions. The former compositions may be defined by their ability toflow, whilst the latter compositions may be defined by their lack ofhardness, having a hardness less than the lesser of 75 grams of force,as measured by the technique described in U.S. Pat. No. 5,516,511(Procter and Gamble), or 500 grams of force, as measured by thetechnique described in U.S. Pat. No. 5,849,276 (Procter and Gamble).Hence, particular embodiments of the invention comprise liquid and softsolid compositions having a hardness such that the pressure required topenetrate the composition is less than 0.06 N.mm⁻².

The various product forms of the invention each have additionalcomponents that are desirably present. Roll-on compositions of theinvention preferably have a low level of non-volatile emollient present,for example isopropyl myristate or propylene glycol at 0.2-2% by weight.Antiperspirant sticks have cyclomethicone as the most preferred carrierfluid. Also preferably present are one or more ethers or esterspreviously mentioned as sensory modifiers; these materials can serve tomask deposits. Wash-off agents are also desirable in such compositions.

Aerosol Compositions

Aerosol compositions of the invention are a particularly preferredproduct form. Preferably the propellant is the major component in suchcompositions, comprising from 30 to 99 parts by weight, more preferablyfrom 50 to 95 parts by weight.

The propellant is normally selected from liquified hydrocarbons orhalogenated hydrocarbon gases (particularly fluorinated hydrocarbonssuch as 1,1-difluoroethane and/or 1-trifluoro-2-fluoroethane) that havea boiling point of below 10° C. and especially those with a boilingpoint below 0° C. It is especially preferred to employ liquifiedhydrocarbon gases, and especially C₃ to C₆ hydrocarbons, includingpropane, isopropane, butane, isobutane, pentane and isopentane andmixtures of two or more thereof. Preferred propellants are isobutane,isobutane/isopropane, isobutane/propane and mixtures of isopropane,isobutane and butane.

Other propellants that can be contemplated include alkyl ethers, such asdimethyl ether or compressed non-reactive gasses such air, nitrogen orcarbon dioxide.

The base composition, which is mixed with the propellant, may compriseany of the following components as preferred additional ingredients: acarrier fluid, a fragrance, an emollient (eg. isopropyl myristate orpropylene glycol) or an anticlogging agent (in order to prevent orminimise the occurrence of solid occlusions in the spray nozzle).Further components may be added to mask powdery deposits, for examplenon-volatile oils, long chain alcohols (eg. octyl dodecanol), ethers(eg. PPG-14 butyl ether), or dimethicone fluids.

The aerosol composition is usually filled into an aerosol canister thatis capable of withstanding pressures generated by the formulation,employing conventional filling apparatus and conditions. The canistercan conveniently be a metal canister commercially available fitted witha dip tube, valve and spray nozzle through which the formulation isdispensed.

Methods of Manufacture

The details of the relevant methods of manufacture depend upon theproduct form concerned. The basic method comprises the mixing of anantiperspirant active, a transition metal chelator, and usually acarrier fluid. Other components are optionally added, according to theform of composition desired.

EXAMPLES

(Note that“letter” codes refer to Comparative Examples.)

Preparation of Aerosol Antiperspirant Deodorants

Example 1 (see Table 1B) was prepared in the following manner. 0.54 g ofquaternium-18-hectorite was gradually added to 5.50 g of volatilesilicone fluid (DC 245, ex. Dow Corning), whilst shearing at a speed ofca. 8000 rpm on a Silverson L4RT mixer (ex. Silverson, Chesham, Bucks.).After approximately 10 minutes, 0.18 g of propylene carbonate was addeddropwise to the mixture. After a further 5 minutes of mixing at 8000rpm, the mixture was removed from the mixer and 0.89 g of DTPA wasslowly stirred in. The resulting liquid was mixed for a further 5minutes and then sealed into a tin plate can, having valve access, and77.66 g of liquified propellant (CAP 40, ex Calor) was introduced intothe can from a propellant ‘transfer can’, via the valve, using apolyethylene transfer device. Finally, the can was fitted with asuitable actuator to enable effective spray application of the product.

Example 2 (see Table 1B) was prepared in a similar manner to Example 1,with the addition of poly(hexamethylenebiguanide) stearate (PHMBS, asdescribed in WO98/56252 [Unilever PLC and NV]) (previously passedthrough a 45 um sieve) at the same time as the DTPA.

Comparative Examples A, B, and C (see Tables 1A and 1B) were prepared ina similar manner to Examples 1 and 2, varying the compositions asindicated.

Deodorancy Tests

The deodorancy performance of the compositions detailed below wereassessed using the following protocol:

A panel was employed comprising 50 individuals who had been instructedto use control ethanolic deodorant products during the week prior to thetest. At the start of the test, panellists were washed with unfragrancedsoap and test product (1.8 g total weight) applied to one axilla andcontrol product applied to the other (1.8 g total weight). (Productapplication was randomised to take into account any left/right bias).Panellists were instructed not to consume spicy food or alcohol, and notto wash under their own axillae, during the duration of the test. Aminimum of three expert assessors determined the intensity of axillaryodour at 5 hours and 24 hours after application, scoring the intensityon a scale of 1-5. After each 24 hour assessment, the panellists werere-washed, and products re-applied, as above. The procedure was repeated4 times. At the end of the test the data were analysed using standardstatistical techniques. The compositions tested and the mean malodourscores observed are detailed in the following Tables. (It must be notedthat data illustrated in different Tables cannot be directly compared,being derived using different panellists in different tests.) TABLE 1AAntiperspirant vs. Antiperspirant + PHMBS¹ Component Example A Example BAACH² 5 5 DC245³ 7.3 7.257 Bentone 38V⁴ 0.5 0.5 Propylene carbonate⁵ 0.20.2 PHMBS¹ 0 0.043 CAP40⁶ 87 87 Mean  5 hour 1.83 1.91 malodour 24 hour1.89 1.96 intensity⁷All components are expressed as weight per cent of the totalcomposition.¹Poly(hexamethylenebiguanide) stearate.²Activated aluminium chlorohydarte, type A296, ex. Guilini.³Volatile silicone, ex. Dow Corning.⁴Structurant, quanternium-18-hectorite, ex. Rheox.⁵Co-structurant.⁶Propellant, proprietary mix of butane, isobutane and propane, Ex.Calor.⁷Differences in values not significant at the 95% level. (Minimumdifferences required for significance at the 95% and 99% confidencelevels were: after 5 hours: 0.09 for 95% level; 0.12 for 99% level;after 24 hours: 0.10 for 95% level; 0.13 for 99% level.)

The results in Table 1A indicate that the addition of 0.043% PHMBSanti-microbial to 5% AACH antiperspirant does not lead to an improvementin the deodorancy performance. TABLE 1B Effect of Added ChelatorComponent Example C Example 1 Example 2 AACH 5 5 5 DC245 7.2 6.2 6.16Bentone 38V 0.6 0.6 0.6 Propylene carbonate 0.2 0.2 0.2 DTPA¹ 0 1.0 1.0PHMBS 0 0 0.043 CAP40 87 87 87 Mean malodour  5 hour 1.84 1.73 1.67intensity² 24 hour 2.05 1.90 1.88All components are expressed as weight per cent of the totalcomposition.¹Diethylenetriaminepentaacetic acid.²The difference in mean malodour intensities between examples C and 2was significant at the 99% level after 5 hours. After 24 hours, thedifferences between C and 1 and between C and 2 were both significant atthe 99% level. (Minimum differences required for significance at the 95%and 99% confidence levels were: after 5 hours: 0.12 for 95% level; 0.16for 99% level; after 24 hours: 0.12 for 95% level; 0.15 for 99% level.)

The results in Table 1B indicate that the addition of 1% DTPA chelatorto 5% AACH antiperspirant leads to a significant improvement in thedeodorancy performance. In the presence of 0.043% additionalanti-microbial (PHMBS) the difference is significant after 5 hours, aswell as after 24 hours. These latter results are in marked contrast tothe effect of added PHMBS in the absence of chelator (Table 1A), whereno benefit is observed.

The benefits observed after 24 hours indicate that prolonged maintenanceof malodour reduction results from the use of the compositions of theinvention; this is a direct result of the prolonged anti-microbialactivity of the compositions.

Anti-microbial Performance of Chelators

An axillary isolate of Staphylococcus epidermidis was grown overnight in100 ml of tryptone soy broth (TSB, Oxoid Ltd). 10 ml of this culture wastaken and subjected to centrifugation. The separated cells werere-suspended in 10 ml of phosphate buffered saline and thecentrifugation procedure repeated. The washed cells were re-suspended in10 ml of phosphate buffered saline to give the inoculum. 100 μl of theinoculum was added to 100 ml of semi-synthetic medium (SSM) containing(NH₄)₂SO₄ (0.066 g), MgSO₄.7H₂O (0.012 g), KCl (0.1 g), KH₂PO₄ (0.27 g),Na₂HPO₄ (1.43 g), thiamin (0.1 mg), biotin (0.05 mg), Peptone P (0.05g), and glucose (2.0 mmole) which had been previously sterilised byautoclaving at 121° C. for 20 minutes. The pH of the SSM was adjusted to6.7 with HCl after sterilisation, prior to addition of the inoculum.This control medium was utilised in all of the in vitro inhibitionstudies. The chelator-containing test media were prepared in a similarmanner, the chelator being introduced at a concentration of 3×10⁻⁶mol.dm⁻³ before the pH adjustment with HCl.

100 μl of the S. epidermidis inoculum was introduced into the controlmedium and into test media containing the chelators indicated in Table2. The cultures were inoculated at 37° C. (with agitation at 200 rpm)for 16 hours, and the optical density of the cultures measured at 600 nmto determine the extent of bacterial growth. By comparison of theoptical density of the culture in the presence of chelating agent, tothat of the control, the percentage inhibition of growth wasestablished. (Optical density measurements were made on 1 in 4 dilutionsof the cultures with 0.9% (w/v) saline, using 1 cm path length cuvettes,on a Pharmacia Biotech Ultrospec 200 Spectrophotometer.) TABLE 2 Resultsof Anti-microbial Performance Tests Chelator Inhibition of growth (%)EDTA 0 CDTA 12.3 DTPA 56.5 TTHA 56.3

These results indicate that DTPA and TTHA meet the criterion to beconsidered preferred “micro-molar active” chelators, whilst CDTA andEDTA fail this criterion.

Preparation of Stick Antiperspirant Deodorants

The stick antiperspirant deodorant compositions indicated in Table 3were prepared in the following manner. The stearyl alcohol, hydrogenatedcastor oil, volatile silicone DC245, and PEG-8 distearate were heatedunder reflux at 85° C., with stirring, until all solids were melted. Tothe mixture was added Suprafino talc and the antiperspirant salt. ForExamples 3 and 4, the DTPA and Cosmocil stearate were added at thispoint. Stirring was continued and the temperature was allowed to fall to60° C. On attainment of this temperature, the compositions weretransferred to plastic stick barrels and left to solidify.

The deodorancy performance of Example 3 and Comparative Example D wereassessed using the aforementioned protocol, with the modification ofusing only 25 panellists and a product dosage of 0.30 g per axilla.TABLE 3 Stick Deodorant Antiperspirants Example Component D 3 4 AZAG¹25.0 25.0 25.0 Suprafino Talc 3.2 3.2 3.2 Stearyl alcohol² 14.0 14.014.0 Hydrogenated Castor Oil³ 4.0 4.0 4.0 PEG-8 distearate⁴ 1.0 1.0 1.0DTPA 0 1.0 3.0 Cosmocil Stearate⁵ 0 0.215 0.215 Volatile Silicone DC245⁶to 100 to 100 to 100 Mean malodour  5 hour 1.60 1.41 — intensity⁷ 24hour 1.77 1.70 —All components are expressed as weight per cent of the totalcomposition.¹Antipersprant salt: AZAG Q5-7167.²Lanette C-18 DEO.³Castorwax MP80.⁴Estol E040DS.⁵Polyhexamethylene biguanide.⁶Cyclomethicone.⁷the Difference after 5 hours was significant at the 95% level. (Minimumdifferences required for significance at the 95% and 99% confidencelevels were: after 5 hours: 0.16 for 95% level; 0.20 for 99% level;after 24 hours: 0.14 for 95% level; 0.18 for 99% level.)

1. An antimicrobial-product comprising an antiperspirant active and atransition metal chelator that is a micro-molar active anti-microbialagent, wherein the ratio of the transition metal chelator to theanti-perspirant active is from 1:3 to 1:50 by weight.
 2. (canceled) 3.An anti-microbial product according to claim 1 wherein the ratio of thetransition metal chelator to the antiperspirant active is from 1:5 to1:25 by weight.
 4. An anti-microbial product according to claim 1,comprising a liquid or soft solid composition.
 5. An antimicrobialproduct according to claim 4, having a hardness such that the pressurerequired to penetrate the composition is less than 0.06 N.mm⁻².
 6. Ananti-microbial product according to claim 1, comprising an aerosolcomposition.
 7. An anti-microbial product according to claim 1, whereinthe antiperspirant active is an aluminium, zirconium, or mixedaluminium/zirconium salt.
 8. An anti-microbial product according toclaim 6, wherein an aluminium halohydrate is a component of the aerosolcomposition.
 9. (canceled)
 10. (canceled)
 11. (canceled)
 12. Ananti-microbial product according to claim 1, wherein the transitionmetal chelator has an acid form comprising at least five acid groups.13. An anti-microbial product according to claim 1, wherein thetransition metal chelator is a polyaminocarboxylic acid or salt thereof.14. An anti-microbial product according to claim 13, wherein thetransition metal chelator is diethylenetriaminepentaacetic acid or asalt thereof.
 15. An anti-microbial product according to claim 1,comprising an additional organic anti-microbial agent.
 16. Ananti-microbial product according to claim 15, comprising apolyhexamethylene biguanide salt, triclosan, or farnesol.
 17. Ananti-microbial product according to claim 1, comprising fragrancematerial at up to 4% by weight of the composition.
 18. (canceled)
 19. Acosmetic method of reducing perspiration and providing additionalcontrol of bacterial numbers on a human body surface, said methodcomprising the topical application to the human body of a productaccording to claim
 1. 20. A cosmetic method according to claim 19,resulting in reduced body odour.
 21. (canceled)
 22. A method for themanufacture of an anti-microbial composition comprising the mixing of anantiperspirant active, a transition metal chelator, and a carrier fluid,wherein the transition metal chelator comprises a chelator capable ofreducing the growth of Staphylococcus epidermidis by at least 30%,pursuant to the procedure set forth in the instant specification underthe heading “Anti-microbial Performance of Chelators”.
 23. Ananti-microbial product according to claim 1 wherein the transition metalchelator comprises ethylenebis[2-(2-hydroxyphenyl)glycine] (EDDHA) or asalt thereof.
 24. An anti-microbial product according to claim 21wherein the transition metal chelator comprises a chelator withphosphonic acid groups, or a salt thereof.
 25. An anti-microbial productcomprising (a) an antiperspirant active, (b) a transition metal chelatorhaving a binding coefficient for iron (III) of greater than 10¹⁰, and(c) an additional anti-microbial agent comprising polyhexamethylenebiguanide salt, triclosan, or farnesol.
 26. An anti-microbial productaccording to claim 25 wherein the transition metal chelator has abinding coefficient for iron (III) of greater than 10²⁶.
 27. Ananti-microbial product according to claim 1 wherein the transition metalchelator comprises a chelator capable of reducing the growth ofStaphylococcus epidermidis by at least 30%, pursuant to the procedureset forth in the instant specification under the heading “Anti-microbialPerformance of Chelators”.